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SAGE-Hindawi Access to ResearchVeterinary Medicine InternationalVolume 2010, Article ID 262604, 9 pagesdoi:10.4061/2010/262604

Research Article

Effects of Supplemental Exogenous Emulsifier on Performance,Nutrient Metabolism, and Serum Lipid Profile in Broiler Chickens

Amitava Roy, Sudipto Haldar, Souvik Mondal, and Tapan Kumar Ghosh

Department of Animal Nutrition, Faculty of Veterinary Science and Animal Husbandry,West Bengal University of Animal & Fishery Sciences, 37 Kshudiram Bose Sarani, West Bengal, Kolkata 700037, India

Correspondence should be addressed to Sudipto Haldar, [email protected]

Received 28 March 2010; Revised 23 April 2010; Accepted 20 May 2010

Academic Editor: Margarethe Hoenig

Copyright © 2010 Amitava Roy et al. This is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The effects of an exogenous emulsifier, glyceryl polyethylene glycol ricinoleate, on performance and carcass traits of broiler chickenswere assessed. The emulsifier was added to the diet at dose rates of 0 (control), 1 (E1) and 2 (E2) % of added fat (saturatedpalm oil). Live weight gain (P < .07) and feed conversion ratio (P < .05) in 39 days were higher in the E1 dietary group. Gain:ME intake and gain: protein intake during the grower phase improved quadratically (P < .05). Gross carcass traits were notaffected. Body fat content and fat accretion increased (P < .05) and liver fat content decreased (P < .05) linearly with the level ofemulsifier in diet. Fat excretion decreased (P < .001) leading to increased ileal fat digestibility (P < .06) in the E1 group (quadraticresponse). Metabolizable intake of N (P < .1) and fat (P < .05) increased quadratically due to supplementation of emulsifier in diet.Metabolism of trace elements and serum lipid profiles were not affected. The study revealed that supplementation of exogenousemulsifiers in diets containing moderate quantities of added vegetable fats may substantially improve broiler performance.

1. Introduction

Inefficient digestion and absorption of fat occurs in youngchickens due to a low level of natural lipase production [1].In chickens the activity and net duodenal secretion of lipaseincreases as the chick ages [2, 3]. A low rate of bile saltsynthesis in young chicks further confounds the problem[4]. Dietary supplementation of bile salt reportedly improvedfat utilization in chicks but the strategy may not be eco-nomically viable [1]. Therefore, cheaper emulsifying agentsor detergents which transform a hydrophobic surface intoa hydrophilic one have been used alternatively to increasefat digestibility in young chicks albeit with variable results[1]. Emulsifiers like soy lecithin promote incorporation offatty acids into micelles and increase fat digestibility in chicks[5]. Synthetic emulsifiers like polyoxyethylene glycol mono-and dioleates have also been tried in pigs although the invivo emulsification of fat by the synthetic emulsifiers was notfound to be as effective as that obtained with bile salts [6].Nevertheless, the exigency of using exogenous emulsifiers inbroiler diets must be looked into because feeding of nutrientdense diets containing added fat is almost inevitable to

exploit the full growth potential of the high yielding broilerstrains.

In this experiment the effect of a synthetic emulsifier,glycerol poly ethylene glycol ricinoleate, supplemented inincremental dose levels, was ascertained in broiler chickens.Being amphiphilic in nature glycerol is essential for theuptake of the free fatty acids which are hardly soluble inbile salt micelles in the gut [7]. It was hypothesized that thesaid emulsifier would facilitate the process of emulsificationin vivo to augment the digestibility of fat and nonfatnutrients including mineral elements. This should improvelive weight gain, food conversion, nutrient metabolizabilityas well as mineral retention. The present investigation wascarried out in a tropical climatic condition where dietaryfat concentration hardly exceeds 3%-4% and one may arguethe justification of an exogenous emulsifier with such amoderate quantity of added fat in diet. The aim of thestudy was to evaluate the dose response to the addedemulsifier on performance and carcass traits, efficiency ofnutrient utilization, and retention of trace elements in broilerchickens fed diets containing moderate quantity of addedfat.

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2. Materials and Methods

Cobb broiler chicks (n = 350, mean live weight 45.2 ±0.89 g) were assigned to three dietary treatments for 39 days.The birds received feed within 12 hours of hatching. Apre-experimental slaughter (n = 20 birds) was performedon day 0. Each treatment group consisted of 9 replicates(n = 12 per replicate) and the replicates were placed inpens (1 m × 1.5 m) on litters composed of saw dust andrice husk. Temperature and lighting hours were maintainedclose to the recommended values [8] and the birds werevaccinated against Marek’s disease, New Castle disease, andinfectious bursal disease. The birds had ad libitum accessto feed and drinking water. The starter (day 1 to 20) andthe finisher (day 21 to 39) diets (Table 1) were formulatedto meet or exceed the requirements [8]. Saturated palm oil(Bergafat HLL, Berg-Schmidt, GmBH and Co., Hamburg,Germany) was the source of supplemental fat. The fattyacid fraction of the supplemental fat was determined by gaschromatography as derivatized fatty acid methyl ester. Alltest diets were mashed and no antibiotic growth promoterwas added. The cocktail enzyme (Enziver, RFCL, New Delhi,India) used in the dietary formulation did not contain lipaseas a component.

The dietary treatments consisted of feeding the birds abasal diet without any added emulsifier (control), and thebasal diet supplemented with glycerol poly ethylene glycolricinoleate, E 484 (Volamel Extra, manufactured by NukamelInc., Hoogbuul, Olen, Belgium) at concentrations of 1% (E1)and 2% (E2) of the added fat (weight/weight). Therefore,each kg of the starter and finisher diets contained 350 mg and280 mg of the emulsifier in the E1 and 700 mg and 560 mg ofthe emulsifier in the E2 dietary groups, respectively.

Live weight, feed consumption, and feed conversionratio (FCR, feed intake g/live weight gain g) were measuredreplicate wise at every 10 days interval and the cumulativelive weight gain and FCR in 39 days was calculated. Mortality,if any, was recorded and the aforementioned measurementswere adjusted for mortality.

Apart from the pre-experimental slaughter, chicks weresacrificed on day 20 (3 birds per replicate) and day 39 (4 birdsper replicate). The birds were killed after an overnight fastby exsanguination and the carcass were stored at –20◦C foranalyses. The hot carcass weight (after removal of the head,blood, neck, and hocks), eviscerated carcass weight and theyields of breast, frame, legs, wings, abdominal fat pad, andgiblets (liver, heart, lungs, and gizzard) were determined onday 39. Breast weight included the breast fillet and the tenders(pectoralis major and minor) and the frame was defined asthe eviscerated body frame with the head, neck, wings, legs,and breast removed. Moisture, protein, and fat in bonelessmeat samples of day 0, 20, and 39 were determined [9].Samples for meat analysis were prepared by taking half of thelongitudinally split carcass (including half of the abdominalfat pad) which were minced and mixed thoroughly untila subsample weighing approximately 500 g was achieved.Meat protein (N × 6.25) was determined in an automatedKjeldahl distillation apparatus (Kel Plus Calssic DX, PelicanEquipments, Chennai, India). For estimation of fat in meat

and liver the moisture free dry samples were ground topass through a 0.5 mm sieve and extracted with petroleumether in an automated ether extract assembly (Socs PlusSCS 4, Pelican Equipments, Chennai, India) for 24 hourswith the ether being changed at intervals of 8 hours. Allthe values concerned with the chemical composition of meatwere expressed on fresh weight (FW) basis. Accretion of theaforesaid nutrients was determined between days 1 to 20, 21to 39, and 1 to 39.

Blood was collected during the pre-experimental slaugh-ter (n = 20) and subsequently on days 20 (n = 3per replicate) and 39 (n = 4 per replicate) and theserum obtained thereof was stored at −20◦C. Concentra-tions of glucose, total protein, albumin, cholesterol, HDL-cholesterol, and triacylglycerol in serum were determinedin a semiautomatic blood biochemistry analyzer (Microlab200, Merck, manufactured by Vital Scientific, Dieren, TheNetherlands) using commercial kits (manufactured by Med-Source Ozone Biomedicals, Faridabad, India). All the assayswere performed in duplicate and an intra assay variation ofmore than 5% was considered to be invalid and a fresh assaywas performed.

A metabolism trial was conducted at the end of thefeeding trial. The replicates, each containing 5 birds, weretransferred to metabolism cages and placed there for 7days including a collection period of 5 days. During themetabolism trial the amount of the food offered and thatof the residues left was measured replicate wise accurately.The excreta were removed at every 2 hours interval and putin self-zipped polyethylene sachets and the total amount ofexcreta obtained in a 24 hours period was weighed. Theexcreta were manually mixed and a subsample measuring(1/20)th of the total excreta volume was kept daily in a hot airoven at 80◦C for 16 hours to determine the dry matter (DM),organic matter (OM), and crude fat [8]. Another sub samplemeasuring (1/20)th of the total excreta volume was collectedin broad mouth plastic containers for 5 days, pooled replicatewise and frozen at −20◦C till analyzed for N and CP [8]. Thediet was also analyzed for the above nutrients.

Metabolizability of DM and fat was determined with 3birds per replicate at the end of the metabolism trial. Thebirds were selected randomly, slaughtered and the entiregastrointestinal tract was immediately exposed after splittingthe carcass longitudinally. The ileum (from the Meckel’sdiverticulum to the ileocaecal junction) and the caecum wereseparated from the rest of the intestine and the contentspresent therein were separately collected by gently flushinginto porcelain crucibles. Ileal digesta and caecal contentsfrom birds within a replicate were pooled replicate wise,dried and stored at −20◦C pending analysis of DM and fat.The contents recovered from the ileum and the caecum wereconsidered to be undigested and the values were used forcalculating the metabolizability of DM and crude fat.

Excretion and apparent absorption of copper (Cu), iron(Fe), manganese (Mn) and zinc (Zn) during the metabolismtrial were determined. Approximately 2 g of oven driedfeed and excreta sample was ignited in quartz crucible at550◦C for 4 hours. The cooled sample was treated with3N nitric acid and boiled for 10 minutes under cover.

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Table 1: Ingredients and chemical composition of the basal diet (g/kg as fed, unless stated other wise)a,b.

Ingredients Starter Grower Chemical composition (calculated) Starter Grower

Maize 517.8 631.6 ME MJ 12.6 13.0

Soybean meal 412.0 314.0 Crude protein 232 195

Palm oil 35.0 28.0 Lysine 13.4 11.1

Limestone powder 9.0 7.0 Methionine 4.52 3.79

Di-calcium phosphate 12.6 6.5 Calcium 8.6 6.4

Sodium-bi-carbonate 1.1 1.1 Available phosphorus 4.3 3.2

Common salt 2.0 2.0 Sodium 2 1.5

Choline chloride (60%) 0.7 — Chlorine mg 1850 1250

Lysine sulfate 1.4 1.6 Total digestible amino acids

DL-methionine 2.3 1.9 Lysine 11.5 9.5

Threonine 0.3 0.5 Methionine 4.3 3.6

Mycotoxin binder 1.0 1.0 Methionine + cysteine 8.3 7.1

Ascorbic acid 0.1 0.1 Tryptophan 1.8 1.6

Organic acid blendc 1.0 1.0 Threonine 7.1 6.1

Cocidiostat 0.5 0.5 Arginine 12.1 10.3

Cocktail enzymed 0.2 0.2 Isoleucine 7.5 6.4

Vitamin premix 2.0 2.0 Valine 8.9 7.5

Trace element premixe 1.0 1.0aThe starter and the finisher diets were fed from days 1 to 20 and 21–39, respectively.bThe basal starter and finisher diets were supplemented with a nutritional emulsifier (glyceryl poly ethylene glycol ricinoleate, E 484, Volamel manufacturedby Nukamel Inc., Hoogbuul, Olen, Belgium) at the dose rates of 0%, 1%, and 2% of the added fat (weight/weight).cContains (per kg) ortho-phosphoric acid (400 g), formic acid (150 g), propionic acid, and calcium propionate (30 g) mixed with a carrier.dEnziver, manufactured by RFCL, New Delhi, India (contains protease, pectinase, cellulose, phytase, xylanase, amylase and ß-glucanase but no lipase).eContained (per kg) manganese 90 g, zinc 80 g, iron 90 g, copper 15 g (all as sulfate salt), iodine (as potassium iodide) 2 g, selenium (as sodium selenite) 0.3 g.

The treated sample was filtered into a 50 mL volumetricflask and diluted up to the mark with deionized water(obtained from a Milipore Water Purification System, Elix 3,Mosheim, France). The concentration of Cu, Fe, Mn, and Znwas determined in an atomic absorption spectrophotometer(Perkin Elmer A Analyst 100, Wellesley, USA). To reduceinterference due to presence of excess of Fe in samples asolution of ammonium chloride (20 mL/L) was added to thestandard and the samples. Apparent retention coefficient wascalculated as

[Trace element∗ feed intake− trace element∗ excreta]Trace element∗ feed intake

.

(1)

All data were analyzed by multivariate analysis of vari-ance in the general linear model (GLM) of the StatisticalPackage for Social Sciences [10]. The replicates were theexperimental units and the concentration of supplementalemulsifier was the main effect. Data involving measurementat different time intervals (day) were analyzed by therepeated measure of GLM in which the effects of diet(dose of emulsifier), day (period of measurement) and diet-day interaction were determined. Orthogonal polynomialcontrasts were applied to determine if the dose response waslinear or quadratic. The data obtained prior to the start ofthe experiment were used as covariates. A probability valueof P < .05 was described as statistically significant and that ofP < .1 was described as a trend.

3. Results

Chemical composition of the starter and the finisher diets(Table 2) conformed to the requirements. The fatty acidfractions of the supplemental fat indicated that it contained80% palmitic acid (C16:0) and 5% stearic acid (C18:0). Thedegree of unsaturation was not of much significance with theC118:1 oleic acid constituting approximately 10% and C18:2

linoleic acid constituting 2% of the total lipid fraction of thefat source. The total fatty acid content was found to be 97%.

The birds remained healthy and consumed their dailymeal allowances throughout the experiment. No mortalitywas recorded in the E2 dietary group during the growerphase. It was intriguing to note that 40% of the birds fed thecontrol diet developed pasty vent within the first 4 days of theexperiment. The figure stood at 15% and 10%, respectively,in the E1 and E2 dietary groups during this period. Thebirds received no veterinary treatment and the conditiondisappeared altogether in the latter two dietary groups by day15 of the trial. However, in the control group more than 18%of the birds were still suffering from pasty vent condition(Table 3).

Live weight and live weight gain in 39 days was higher(P < .07) in the E1 dietary group. Cumulative feed con-sumption was similar across the dietary treatments (P > .1)although, during the grower phase the E1 group of birdsconsumed less food for each unit of live weight gain relativeto the control and the E2 dietary groups (P < .05, quadraticeffect). Numerically, overall feed: gain ratio in 39 days


Table 2: Chemical composition of the experimental diets (analyzedvalues).

Attribute Growth phaseDieta,b

Control E1 E2

Nutrients g/kg

MoistureStarter 173.1 176.3 172.8

Grower 175.5 176.1 173.4

Organic matterStarter 907 917.1 90.4

Grower 915.6 917.7 918.3

Crude proteinStarter 229.3 230.1 230.4

Grower 193.3 194.5 195.3

Crude fatStarter 46.1 46.5 47.2

Grower 53.9 56.8 56.9

Crude fiberStarter 36.1 36.5 36.8

Grower 34.2 33.9 34.1

Trace elements mg/kg diet dry matter

CopperStarter 14.7 14.2 14.5

Grower 19.7 21.5 20.6

IronStarter 1031 1024 1016

Grower 1604 1547 1502

ManganeseStarter 141.9 146.1 145.2

Grower 153.8 150.8 150.9

ZincStarter 118.5 124.9 120.1

Grower 111.2 107.3 110.8aAnalyzed on dry matter basis except moisture and organic matter;bSupplemented with emulsifier at the dose rates of 0 (control), 1 (E1) and 2(E2) percent of added fat (weight/weight basis).

improved by approximately 5% in the E1 dietary grouprelative to that in the control group. Utilization efficiencyof ME (gain: ME intake and gain: CP intake), which wasnot affected during the starter phase (P > .1), increasedquadratically (P < .05) in the E1 dietary group during thegrower phase compared to those in the control and the E2dietary groups (Table 3).

Supplemental emulsifier did not affect (P > .1) the grosscarcass traits (Table 4). Meat protein was found unchangedwhen measured on day 20 and day 39 (day effect P > .1) andsupplemental emulsifier had little effect on this parameter(P > .1). Meat fat content increased with age (day effectP < .001) particularly in the E1 and E2 dietary groups(diet effect P < .001, linear effect, diet × day interactionP < .01). Consequently, fat accretion also increased linearly(P < .05) with the level of emulsifier in diet. Liver fatcontent decreased linearly (P < .05) with increasing levelof emulsifier in diet and a diet-day interaction (P < .01)indicated towards an age-dependent effect of the emulsifierin this regard. Consequently, fat accretion in liver also tendedto decrease linearly (P < .06) with the dose of the emulsifierin diet.

Supplemental emulsifier increased the metabolizabilityof DM and fat (Table 5). The ileal DM content was quadrat-ically higher (P < .02) in the E1 dietary group and thecaecal DM content was lower in the said group (P < .001,

linear effect; P < .04, quadratic effect) compared to thosein the control and the E2 dietary groups. Fat content inthe ileum of the control and the treated groups was similar(P > .1). However, the caecal fat content decreased linearlywith the dose of the emulsifier (P < .05) leading to anincreased metabolizability of fat in the E1 dietary group(P < .1).

Added emulsifier had subtle effect (P > .1) on DM, OM,N and fat intake (Table 5). Excretion of N (P < .001, lineareffect; P < .02 quadratic effect) and fat (P < .001, linearand quadratic effect) decreased with the dose of emulsifier.Excretion of DM and OM was not affected (P > 01) dueto varying levels of added emulsifier and hence, intake ofmetabolizable DM and OM was similar across the treatmentgroups (P > .1). Metabolizable N intake tended to be higher(P < .1) and that of fat increased linearly (P < .05) with thedose of added emulsifier in diet (Table 5).

Intake, excretion and apparent absorption coefficient ofthe trace elements were mostly unaffected (P > .1) bysupplementation of emulsifier to the diet (Table 6). Excretionof Zn increased linearly in the E1 and E2 dietary groupscompared to that in the control group of birds (P < .05)although the apparent absorption coefficient of Zn was notaffected. Apparent absorption coefficient of Cu was quitevariable with the E1 group of birds showing higher Cuabsorption than that in the control and the E2 dietary groups(P < .05).

Supplemental emulsifier had variable effects on serummetabolites (Table 7). Serum glucose increased linearly withthe dose of supplemental in diet (P < .01). Serum glucoseincreased (day effect P < .001) as age of the birds advanced.Total protein and albumin concentrations were similar(P > .1) across the treatments. Total cholesterol and LDLcholesterol decreased linearly with the level of emulsifier indiet (P < .05) on day 20 although the difference disappearedon day 39 (P > .1). However, HDL cholesterol fractionremained unaffected (P > .1) by the level of emulsifier indiet. The HDL : LDL ratio widened (P < .05, linear effect)in the E1 and E2 groups day 20 although on day 39 theratio was similar across the dietary treatments (P > .1).Added emulsifier exerted non significant effect in serumtryacylglycerol concentration (P > .1). It was observedfurther that irrespective of the level of emulsifier in dietserum tryacylglycerol concentration decreased (P < .001)with age.

4. Discussion

Fat content in the starter E1 and E2 diets was 1.6% and3.9% higher than that in the basal diet. During the finisherphase fat content was 5.9% and 6.6% higher in the E1 andE2 diets, respectively, than that in the basal diet. Additionof the emulsifier, which was nothing but fat per se (ricinusoil ester) added to the crude fat content of the E1 E2diets. Dietary concentration of trace elements exceeded therequirement [8] because prior to adding the mineral premix,concentration of the trace elements in dietary ingredientswas not considered and so no adjustment was made in thisregard.


Table 3: Live performance of broilers supplemented with exogenous emulsifier in graded dosesa.

Response variables DayDietary treatment

SEDiet effect (contrast P)

Control E1 E2 Linear Quadratic

Performance traits

Mortality (n)1–20 2 2 1

21–39 1 1 Nil

Pasty vent (%)1–10 40 15 10

11–20 18.1 Nil Nil

21–39 Nil Nil Nil

Live weight g

1 51.2 50.8 51.4

10 264 268 269 1.92 .26 .86

20 787 801 794 5.59 .63 .37

30 1392 1438 1387 18.8 .92 .24

39 2035 2136 2055 29.5 .76 .07

Live weight gain g20 736 750 742 5.6 .64 .07

39 1983 2085 2004 28.8 .77 .16

Food : gain1–20 1.51 1.50 1.51 0.04 .99 .93

21–39 2.08 1.93 2.07 0.03 .96 .05

1–39 1.86 1.77 1.86 0.02 .31 .13

Gain : ME intake1–20 53.2 53.2 52.8 1.34 .9 .94

21–39 35.5 38.3 35.7 0.69 .94 .05

1–39 40.5 42.6 40.5 0.58 .98 .11

Gain : CP intake1–20 2.93 2.92 2.89 0.073 .89 .96

21–39 2.49 2.67 2.48 0.043 .93 .05

1–39 2.64 2.76 2.62 0.037 .82 .06aEach treatment group consisted of 9 replicates (1–20 days, n = 12 per replicate; 21–39 days, n = 9 per replicate).

Table 4: Gross carcass traits and chemical composition of meat and nutrient accretion in broilers supplemented with exogenous emulsifierin graded doses (means of 3 birds/replicate on day 20 and 4 birds/replicate on day 39).




Gross carcass traits g

Eviscerated carcass 39 1069 1137 1056 30.5 .87 .26

Breast 39 386 418 368 12.9 .57 .16

Legs 39 353 375 351 13.4 .97 .43

Abdominal fat20 4.9 4.1 6.1 0.12 .39 .41

39 19.2 20.2 16.9 0.89 .81 .88

Chemical composition of meat and liver g/kg fresh weight

- Meat

Protein20 204 198 203 1.7 .77 .16

39 200 196 208 2.9 .29 .21

Fata 20 13.5 17.2 30.7 0.73 .0001 .007

39 20.9 29.7 30.9 1.61 .02 .28

- Liver

Fatb 20 32.4 28.3 24.1 0.21 .01 .12

39 34.3 31.7 29.2 0.71 .02 .39

Liver fat accretion mg/day (1–39 day) 39.8 33.5 23.1 3.16 .43 .06

Nutrient accretion g

Protein 1–20 144 143 145 1.93 .95 .67

21–39 247 259 267 7.26 .29 .89

Fatc 1–20 9.7 12.9 23.5 0.55 .0001 .007

21–39 32.4 49.7 38.3 2.96 .43 .037aDay-diet interaction P = .01; bDay-diet interaction P = .002; cDay-diet interaction P = .02.


Table 5: Nutrient concentration in ileum and cecum and metabolizability of nutrients in broilers supplemented with graded levels ofnutritional emulsifiera.

Response variablesDietary treatment



Nutrient concentration in ileum and cecum g/kg digesta

Ileal DM 189.9 207.7 185.7 3.55 .64 .02

Cecal DM 181.7 166.9 180.7 4.77 .0001 .04

Ileal fat 26.4 25.8 28.7 0.97 .35 .41

Cecal fat 36.1 31.2 34.8 0.23 .045 .0001

Metabolizability of nutrients

Intake g/day

DM 185 191 184 3.77 .9 .4

OM 169.9 175.9 169.6 3.42 .98 .41

N 5.31 6.01 5.53 0.28 .75 .32

Fat 9.89 10.5 10.4 0.24 .41 .46

Excretion (% intake)

DM 28.7 24.9 28.9 1.15 .94 .12

OM 6.13 5.31 6.16 0.24 .95 .12

N 46.4 19.6 21.3 2.64 .001 .02

Fat 11.8 3.16 4.00 0.6 .0001 .0001

Metabolizable intake g/day

DM 132.9 143.9 130.9 4.22 .86 .19

OM 159.6 166.6 159.2 3.44 .96 .34

N 3.09 4.96 4.39 0.29 .08 .06

Fat 8.74 10.19 9.96 0.25 .05 .12an = 9 per replicate (each replicate consisted of 5 birds during the metabolism trial).

Table 6: Intake (mg/kg diet DM), excretion (mg/kg excreta DM), and apparent retention coefficient of trace elements in broilers during themetabolism trial (day 41–45) supplemented with graded levels of emulsifiera.

Response variablesDietary treatment



Intake

Copper 14.1 14.3 13.9 0.16 .56 .45

Iron 1573 1570 1555 5.89 .21 .6

Manganese 147 148 140 3.26 .39 .47

Zinc 109 109 108 0.79 .64 .78

Excretion

Copper 8.4 9.3 10.8 1.19 .43 .2

Iron 905.5 913.1 917.4 8.14 .56 .92

Manganese 106.3 102.4 100.6 1.55 .15 .76

Zinc 63.2 66.3 66.6 0.54 .02 .23

Absorption

Copper 0.291 0.367 0.213 0.04 .02 .06

Iron 0.383 0.303 0.36 0.03 .78 .36

Manganese 0.207 0.18 0.207 0.05 .99 .8

Zinc 0.375 0.272 0.332 0.04 .64 .31an = 9 per replicate (each replicate consisted of 5 birds during the metabolism trial).

Supplementation of emulsifier in incremental dose levelswas expected to enhance utilization efficiency of dietary fat[7, 11] and improve live weight gain and feed conversionin broiler chickens. Conforming to the postulation therewas 5% increment in live weight in the E1 dietary grouprelative to the control group of birds. Additionally, thebirds supplemented with emulsifier markedly recovered frompasty vent condition perhaps due to better utilization of

dietary fat. Improved utilization efficiency of ME and CPin the emulsifier supplemented birds during the growerphase, indicated positive effects of the emulsifier on digestionand absorption of fat as well as other nutrients. However,the quadratic dose responses suggested that with moderatequantities of fat added to diet, little benefit could be obtainedif the concentration of supplemental emulsifier exceeds 1%of the added fat. The need of an emulsifier in broiler diet is


Table 7: Serum metabolite profile in broilers supplemented with graded levels of nutritional emulsifiera.


S.E.Diet effect (contrast P)


Glucose mmol/L20 4.36 4.18 4.71 0.11 .22 .16

39 8.09 7.82 9.64 0.12 .01 .04

Total protein g/L20 36.6 37.7 33.7 1.03 .3 .25

39 43.8 41.0 45.2 0.91 .68 .26

Albumin g/L20 15.3 15.4 15.7 0.56 .7 .9

39 12.3 12.7 11.9 0.53 .6 .9

Cholesterol mmol/L20 5.46 4.13 3.88 0.32 .04 .43

39 4.62 5.09 5.01 0.16 .43 .52

HDL cholesterol mmol/L20 0.862 0.849 0.905 0.05 .74 .55

39 0.998 0.909 0.935 0.04 .75 .54

LDL cholesterol mmol/L20 4.6 3.28 2.97 0.29 .04 .44

39 3.61 4.18 4.08 0.16 .38 .46

HDL : LDL20 0.209 0.258 0.332 0.028 .09 .04

39 0.288 0.221 0.256 0.02 .52 .26

Tryacylglycerol mmol/L20 1.35 1.43 1.06 0.08 .55 .59

39 0.7 0.79 0.71 0.11 .98 .68aData represent pooled mean of 9 replicate in each treatment group.

more during the starter phase [12] because lipase activity inchickens reaches the peak only between 40 and 56 days ofage [13]. Moreover, synthesis and recirculation of bile saltsremain at a much lower plane in young chickens [14–16] andbile salts added to diets reportedly improved fat absorption inyoung chickens [5] and augmented productive performance[6, 7, 11, 17–19]. The results of the present investigation indi-cated the benefits of dietary supplementation of emulsifiersin grower phase also thus adding to the current status ofknowledge.

It appeared from the liver fat content that supplementa-tion of emulsifier probably facilitated shunting of fats moretowards body depot and reduced fat deposition in liver[19]. As a result, fat accretion in whole body increased byapproximately 50% in the emulsifier fed birds over that inthe control group.

Subtle change in meat protein occurred despite greaterutilization efficiency of CP particularly in the E1 group.This discrepancy could not be explained. However, CPutilization efficiency improved during the grower phase onlyand perhaps there was little room available for the muscleprotein content to change during the entire course of theexperiment.

Positive effect of emulsifiers on digestibility of nutrientsis documented in pigs [7, 11, 19]. Supplemental emulsifierin the present study increased intake of metabolizable N andfat. Metabolizable N intake increased by 60.5% and 42.1%,respectively, in the E1 and E2 dietary groups over that inthe control group of birds. Metabolizable fat intake alsoimproved by approximately 17% and 14%, respectively, inthe E1 and E2 dietary groups relative to the control group.

Supplementation of emulsifier improved metabolizabil-ity of DM and fat. However, the quadratic dose response

confounds the justification of increasing the dose of theemulsifier beyond 1% of the added fat and warrants furtherresearch. The results corroborated an earlier work with pigs[20]. Lecithin reportedly depressed free fatty acid absorptionfrom rat jejunum probably by increasing size of bile saltmicelles which defuse more slowly through the luminalwater interface and retarded delivery of free fatty acids tothe absorptive cell surface [21]. Another possibility is thatpersistence of lecithin-bile salt micelles at the absorptivecell surface may alter free fatty acid partitioning. Free fattyacid absorption could be reduced if they prefer the aqueousenvironment of the mixed micelles rather than the lipidmembrane of the absorptive cell surface [21]. Comparedto lecithin, glyceryl polyethylene glycol ricinoleate is morehydrophilic and dissolves the free fatty acids which are hardlysoluble in bile salt micelle alone [7] and thereby increasesthe digestibility of saturated fatty acids. It is possible thatthe higher concentration of the supplemental emulsifier inthe E2 dietary group caused a greater number of fatty acidmolecules to be released in vivo which were not absorbedefficiently since an excess of free fatty acids in gut lumen mayinterfere with the process of micelle formation [7, 22, 23].The ileal fat content would perhaps support this hypothesis.The higher fat content in the cecum of the experimental birdscompared to that in the ileum might be due to concentrationof the cecal contents that occurred as a result of reabsorptionof water from the cecal contents.

To our knowledge effect of an emulsifier on metabolismof trace elements has not been studied yet. Emulsifiersreportedly improved absorption of calcium and phosphorus[7, 11] although contrasting results are also available [17].Nevertheless, the present experiment did not reveal anysignificant effect of supplemental emulsifier on metabolism


of the trace elements. The variation observed with regard toCu absorption could not be explained and may be ignored asan aberration.

Serum concentration of glucose indicated that more ofthe available glucose was utilized for growth and productionin the E1 dietary group compared to that in the control andthe E2 groups of birds. Serum lipid fractions seemed to bemore vulnerable to the effects of supplemental emulsifier andit was reported that in pig serum tryacylglycerol decreaseddespite an enhancement in fat digestibility when lecithin wassupplemented [11]. It was hypothesized that lecithin causedthe chylomicrons to be cleared off from the blood at a fasterrate or retarded their release into blood at a slower pace,thus lowering circulatory tryacylglycerol concentration. Byaugmenting the process of emulsification, lecithin increasesthe coat (phospholipids): core (tryacylglycerol) ratio ofthe lipoprotein fraction of chylomicrons and stabilizes thelipoprotein particles in the aqueous environment of theblood stream and decreases the release of the free fattyacids and cholesterol in blood [11]. However, insufficiencyof knowledge regarding the effect of glyceryl polyethyleneglycol ricinoleate on postabsorptive absorption of lipid andcirculatory lipid profile precludes a definite conclusion aboutthe exact mechanism that lowered the serum cholesterolconcentration in the emulsifier supplemented birds.

The effect of emulsifier on HDL : LDL fraction of serumlipid in live stock is not ample. In pigs, LDL cholesterolmay decrease when lecithin was fed as an emulsifier whereaslysolecithin raised circulatory LDL cholesterol [11]. How-ever, similar reports with regards to synthetic emulsifiers arenot available. However, the present investigation indicatedthat glyceryl polyethylene glycol ricinoleate may also reducethe cholesterol in serum of chickens. Liver fat concentrationin the experimental groups was also suggestive of an efficientand rapid removal rate of lipids from the liver. However,fractionation of liver lipid content and determination ofcholesterol metabolites in liver is warranted to reach at aconfirmatory conclusion in this regard.

In conclusion, glyceryl polyethylene glycol ricinoleatewas found to be an effective emulsifier for broiler chickenswhen added at concentrations above 1% of the addedfat. At this concentration the emulsifier increased the liveweight by approximately 5% and significantly improved feedconversion efficiency although the effects on carcass traitsseem not to be very pronounced. There was certain effect onfat utilization which was evidenced from improvements intotal tract apparent digestibility of fat and overall fat metab-olizability which could be explored as a tool for enhancingfat utilization in high-yielding chicken fed greater quantityof added fat through diets. Overall, glyceryl polyethyleneglycol ricinoleate may be considered as an inevitable feedadditive component in the dietary regimen of high-yieldingbroiler chickens for augmenting nutrient utilization and foodconversion in broilers.

References

[1] W. Al-Marzooqi and S. Leeson, “Evaluation of dietary supple-ments of lipase, detergent, and crude porcine pancreas on fat

utilization by young broiler chicks,” Poultry Science, vol. 78,no. 11, pp. 1561–1566, 1999.

[2] J. Hakansson, “Factors affecting the digestibility of fats andfatty acids in chicks and hens,” Swedish Journal of AgriculturalResearch, vol. 4, pp. 33–47, 1974.

[3] Y. Noy and D. Sklan, “Digestion and absorption in the youngchick,” Poultry Science, vol. 74, no. 2, pp. 366–373, 1995.

[4] B. T. Jackson, R. A. Smallwood, G. J. Piasecki, A. S. Brown,H. F. Rauschecker, and R. Lester, “Fetal bile salt metabolism. I.The metabolism of sodium cholate-14C in the fetal dog,” TheJournal of Clinical Investigation, vol. 50, no. 6, pp. 1286–1294,1971.

[5] D. Polin, “Increased absorption of lecithin with tallow,”Poultry Science, vol. 59, p. 1652, 1980.

[6] L. T. Frobish, V. W. Hays, V. C. Speer, and R. C. Ewan, “Effectof diet form and emulsifying agents on fat utilization by youngpigs,” Journal of Animal Science, vol. 29, no. 2, pp. 320–324,1969.

[7] N. A. Dierick and J. A. Decuypere, “Influence of lipase and/oremulsifier addition on the ileal and faecal nutrient digestibilityin growing pigs fed diets containing 4% animal fat,” Journal ofthe Science of Food and Agriculture, vol. 84, no. 12, pp. 1443–1450, 2004.

[8] Cobb-Vantress Inc, Cobb Management Guide, Siloam Springs,Ark, USA, 2004.

[9] Association of Official Analytical Chemists (AOAC), “Officialmethods of Analysis” of the Association of Official AnalyticalChemists, Washington, DC, USA, 14th edition, 1984.

[10] SPSS, Statistical Package for Social Sciences (10.0), SPSS,Chicago, Ill, USA, 1999.

[11] D. B. Jones, J. D. Hancock, D. L. Harmon, and C. E.Walker, “Effects of exogenous emulsifiers and fat sources onnutrient digestibility, serum lipids, and growth performancein weanling pigs,” Journal of Animal Science, vol. 70, no. 11,pp. 3473–3482, 1992.

[12] J. L. Sell, A. Krogdahl, and N. Hanyu, “Influence of age onutilization of supplemental fats by young turkeys,” PoultryScience, vol. 65, no. 3, pp. 546–554, 1986.

[13] A. Krogdahl and J. L. Sell, “Influence of age on lipase, amylase,and protease activities in pancreatic tissue and intestinalcontents of young turkeys,” Poultry Science, vol. 68, no. 11, pp.1561–1568, 1989.

[14] J. A. Serafin and M. C. Nesheim, “Influence of dietary heat-labile factors in soybean meal upon bile acid pools andturnover in the chick,” Journal of Nutrition, vol. 100, no. 7, pp.786–796, 1970.

[15] R. A. Smallwood, R. Lester, A. S. Brown, G. J. Piasecki, and B.T. Jackson, “Fetal bile salt absorption,” The Journal of ClinicalInvestigation, vol. 49, article 90a, 1970.

[16] R. A. Smallwood, R. Lester, G. J. Plasecki, P. D. Klein, R. Greco,and B. T. Jackson, “Fetal bile salt metabolism. II. Hepaticexcretion of endogenous bile salt and of a taurocholate load,”The Journal of Clinical Investigation, vol. 51, no. 6, pp. 1388–1397, 1972.

[17] M. ∅verland and F. Sundstøl, “Effects of lecithin on fatutilization by weanling pigs,” Livestock Production Science, vol.41, no. 3, pp. 217–224, 1995.

[18] C. F. Jin, J. H. Kim, I. K. Han, H. J. Jung, and C. H. Kwon,“Effects of various fat sources and lecithin on the growthperformance and nutrient utilization in pigs weaned at 21 daysof age,” Asian-Australasian Journal of Animal Sciences, vol. 11,no. 2, pp. 176–184, 1998.

[19] Y. M. Dersjant-Li and M. Peisker, “Soybean lecithin in animalnutrition: an unmatched additive,” Kraftfutter, vol. 88, pp. 28–34, 2005.


[20] E. Van Heugten and J. Odle, “Evaluation of lysolecithin as anemulsifier for weaning pigs,” ANS Report 248, North CarolinaUniversity Department of Animal Science, DepartmentalReport, Raleigh, NC, USA, 2000.

[21] D. R. Saunders and J. Sillery, “Lecithin inhibits fatty acid andbile salt absorption from rat small intestine in vivo,” Lipids,vol. 11, no. 12, pp. 830–832, 1976.

[22] H. S. Bayley and D. Lewis, “The effect of a non-ionic surfaceactive agent on the digestibility of triglycerides and free fattyacids in the pig,” Proceedings of the Nutrition Society, vol. 22,pp. 32–33, 1963.

[23] A. O. Ajuyah, D. Balnave, and E. F. Annison, “Determinationof apparent and true dietary fatty acid digestibilities andmetabolisable energy using ileal digesta and excreta frombroiler chickens,” Animal Feed Science and Technology, vol. 62,no. 2–4, pp. 131–139, 1996.

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